


Goodbye Sex Gone Wrong

by 96kyonkichi



Category: Haikyuu!!
Genre: Eventual Romance, Goodbye Sex, Knotting, M/M, Mpreg, Not Canon Compliant, Omega Verse, Separations, Single Parents, Unplanned Pregnancy
Language: English
Status: In-Progress
Published: 2020-06-09
Updated: 2020-06-09
Packaged: 2021-03-04 05:14:44
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,663
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24628408
Author URL: https://archiveofourown.org/users/96kyonkichi/pseuds/96kyonkichi
Summary: [ABO AU + Non-canon af] After their high school graduation ceremony, Kageyama Tobio and Tsukishima Kei, both alphas, part ways with a goodbye sex. Too drunk with sexual libido, they end up doing the deed unprotected. Seven years later, Tobio, a single dad (more like, mom) having borne a son out of that passionate night, gets told by his pre-schooler son: “Papa, we have a transfer student today and my classmates are telling me we look similar…”Little did he know, his fateful reunion with the blonde spiker was looming.
Relationships: Kageyama Tobio/Tsukishima Kei
Comments: 4
Kudos: 74





	1. Chapter 1

Author's Note: Pardon this guy who happened to have this sort of twisted mind argh. And apologies in advance because I actually haven’t caught up yet with Haikyuu, so to be safe, I’m making a non-canon AU instead. The beginning of the story is also set somewhere in the late 00’s, before time-skipping. Hope y’all enjoy the product of my rotten mind.

* * *

**Chapter 1**

“Today’s… our last day together.” Tsukishima Kei mutters to himself, clutching the certificate holder of his diploma. He is standing at the rooftop of one of the buildings in Karasuno, the sunset rays tinting his face and hair with bright orange. Beside him is the raven-haired teen Kageyama Tobio sitting on his feet, his mouth shut, his eyes staring at faraway clouds. His arms are crossed while also clutching to his own diploma.

Kei had been going out with _The King_ , Kageyama Tobio, for the past two years. Despite the lack of seriousness with their relationship as proven by their usual bantering, both are now faced with this _separation_ : Graduation.

_They should have known better_ , his mind at least figured that. Graduation is inevitable. They have both chosen different schools for themselves. They had different plans from the start, and something as dumb as _a_ _relationship_ would just impede with their prospects in the future.

The fact that they were both males and alphas were more than taboo to the society, that’s why they chose to hide it at first. Until one day, a certain Hinata Shouyou accidentally walked into them making out. To the orange head’s credit, he didn’t intentionally _reveal_ anything to his teammates, only that being flustered always did him bad and caused him to slip in front of the team.

Was it even romantic attraction? No one knew. But Tobio knew that despite his differences with the blonde, there was something in him that felt attracted, for sure.

As he slowly crept out of reverie into the present, Tobio knew that for sure, this will be their last day. While he does not want to hold on with whatever _relationship_ they had, he decided to take a bold step…

“M- my parents…” He breaks the silence, startling the taller teen. “My parents aren’t home tonight.” Slowly, he shifts his gaze to the bespectacled. “W- want to come over?”

In the setter’s dark room save for the faint neighbors’ lights faintly providing some illumination, they were a tangled mess of muffled voices, moans, and wet noises. They immediately went at it without any hesitation, not even turning the lights on at the setter’s dark room.

Kei himself didn’t hesitate in grabbing the opportunity, the seemingly indirect _invitation_ that Tobio made was too obvious. He knew it would come into this, and his resolve was more than ready, despite not having done this before even though they were _lovers_ for a long time already.

Both are in the midst of the hungry kissing, messy undressing, and uncontrollable rubbing of hands in random erogenous places, up until the two were buck naked, sucking each other’s hard erection. Tobio motioned to insert a finger up Kei’s anus, startling him with a gasp.

“I-idiot! Who said I’m the bottom!?” Kei protested, subtle moans were.

“Well you better be, since I’m first in preparing your ass.” Tobio replied, unfazed, who did not stop his fingers from moving.

Kei may be overwhelmed by the sensation of having his posterior cavern explored, but he knows very well how to pay the favor back. He also inserts a finger up the raven’s butt, in which he groans at the unfamiliar sensation.

They were both alphas. While society would say that their anuses aren’t built to be did things like that, here they are, further aggravating the _deviance_ they have in the society. The room was filled with lewd voices, the two were drowning in debauchery. Up until Kei decides to stop and part his body momentarily with Tobio’s, also removing his glasses and setting them aside.

Kei may be too prideful, but he knows this night will not progress if he wouldn’t set his pride aside. With some hesitation, he declares a deal:

“I’ll let you fuck me, but in return, I’ll fuck you afterwards.”

Tobio blushed at the sudden dirty language uttered by the blocker, but he acknowledged that for them to proceed to the next stage, there has to be some compromise.

“F-fine.”

Soon, the room was noisy with the loud gasps from Kei and grunts from Tobio, who is now completely inside and moving in-out of the former. The blonde is lying on the bed, his hips and thighs raised and legs comfortably positioned on his partner’s shoulders, while the raven thrusts raw at the exposed hole. Tobio swoops down to his lover’s mouth, planting a deep kiss as the base of his penis gradually expanded at the impending release.

Kei, noticing the slowly tightening sensation in his behind, started to realize that they are doing it _raw_ and even with the low chances, he might be _impregnated_ —especially that his partner is _also_ an alpha.

“N- no… pull it out… don’t… cum inside…” Tsukishima protested amid moans.

Alas, it was too late. With one forceful thrust, Tobio let out a loud grunt as his seed slowly spilled inside Kei, his member already enlarged and locked inside Tsukishima’s cavity.

_‘No good, we will be stuck like this for the next several minutes’_ , Kei mutters inside his mind, a mix of irritation and arousal filled his consciousness as he felt the steady stream of warm seminal fluid fill his insides.

Tobio managed to lay his own weight on Kei. He again locked lips with the blonde, their tongues in a wet battle as he felt both his _manly essence_ and all his energy slowly drain from him.

After what felt like eternity, Kei could now feel Tobio’s member shrink, until the other alpha’s dick just popped out of his sticky wet hole on its own.

_It’s payback time_.

Just as Tobio was about to crash into the bed, Kei caught him, saying with a sinister smile on his face: “We aren’t done yet, King.”

The taller teen seated himself in the bed and proceeded to lift the shorter by the thighs, in such fashion where Tobio, whose weak legs are spread against his partner’s body, is now seated on Kei’s lap.

“I guess I’ll be cumming inside you, too.” Kei’s eyes were staring sharply at the now weakened setter, whom he now has to embrace just so they could maintain their position.

Kei didn’t mind his leaking ass dirtying the sheets of the now helplessly weak and moaning lewdly alpha. He thrust consistently as he also lifted and lowered Tobio repeatedly. The goal has changed from just doing _it_ at least once before they parted ways, into vengefully ejaculating his semen inside The King.

The rhythm gradually grew pace. Tobio was moaning lustfully at every move as Tsukishima grunted, staring intently at his partner’s lewd face. As he felt his own engorged member grow at the base, he thrusted more forcefully than ever.

“T- Tobio…!” Kei called his lover’s name out.

“K… Kei…!” The setter uttered back.

Both mouths motioned to hungrily devour each other before Kei let out one final grunt before thrusting for the last time, spilling his hot semen inside the raven’s rectum as his dick comfortably locked itself tight into place.

For the next several minutes, as Tsukishima’s penis continued to leak and fill Kageyama’s hole, they stayed in the same position, hungrily kissing each other like it’s their last — well, of course, it _is_ their last.

Kei started to feel weak. He parted his mouth from Tobio’s and proceeded to look at him, smiling faintly and still breathing heavily.

“That… that felt good…”

“Sure… did…” Tobio replied, also panting moderately.

Kei wrapped his arms around Tobio, binding their sticky bare chests together. Both of the can feel each other’s heavily pounding chests, their body warmth exchanging.

“Is it really okay to part ways after this…?” Kei feebly said.

“Idiot… it’s not like we were extremely emotionally bonded to begin with…” Tobio replied with the same level of exhaustion as the other alpha.

“Ah… right…” The blonde muttered to agree.

“Besides… each of our future plans are more important…” Tobio, feeling the tightly plugged erection on his ass slowly shrink and slide out, parted his body from Kei to kiss yet once more. Once the blonde alpha’s appendage got freed, he felt his behind agape before feeling the warm fluid leak from his hole.

They were too spent to get up and at least clean up. Tobio pulled his sheets to cover their naked bodies and they both fell into deep slumber in each other’s arms.

The next day, Kei leaving Tobio’s house meant that it would be the last time they’d see each other… unless there are opportunities for them to reunite.

“You sure your body’s okay?” Tobio asks as he looks at Kei who is in the process of wearing his shoes at entrance of the Kageyama residence.

“More than fine, though…” Kei glanced momentarily at the shorter alpha before looking again towards his feet.

Kei finishes, and stands up.

“You know, I don’t know when we will ever meet again.” Kei began, speaking with a serious face. “But I am sincerely hoping for the best prospects of your life.”

Tobio looks at him with a disapproving, almost disgusted face. “That’s… so unlike you though. But thanks…”

The raven averts his eyes and a few moments of silence, before pouting his mouth to reluctantly say:

“…Thank you… for the relationship we had in the past two years.”

“Thank you, too.” Kei starts walking towards Tobio, staring intently. Grabbing the back of the raven’s head, the blonde alpha locks their mouths together for a few moments before pulling away.

“I hope that’s enough for a goodbye kiss.” Kei snarkily said to the raven alpha as he motioned to the door to leave.

Tobio followed, the two of them walking outside. They gave each other one last gaze before Kei went off his way, leaving Tobio behind.

Seven weeks after high school graduation, Tobio was settling in his apartment shared with his former senpais Sugawara Koushi and Sawamura Daichi.

One morning, Tobio was washing the breakfast dishes when he suddenly felt uncomfortable, gradually sick. He felt something like a rush inside his head, forcing him to stop his work. Without a warning, he was throwing up on the sink, which both Daichi and Suga heard, causing them to rush to his side.

“Tobio!? You okay?” Suga calmly asked, but the worry was evident on his face.

“Y- yes… I’m fine…” Tobio asked, the discomfort obvious in his face, before yet one more time hurling at the sink.

“Y- you sure this isn’t food poisoning? How about we bring him to the hospital?” Daichi asked Suga.

And thus, they went to the hospital.

The look of concern on the two senpais were relieved when they were informed by the doctor that it wasn’t food poisoning.

Suga sighs in relief. “Then what is it, doctor?”

The doctor, with piercing eyes in seriousness, sharply told them:

“He’s around seven weeks pregnant.”

“Tobio, what’s the meaning of this??” Suga was intensely puzzled by the sudden turn of events. “You’re… an alpha, right…?”

Tobio, himself, was in shock at the news and was at loss for words. He was just staring blankly at the floor.

Daichi intervenes. “Stop it, Suga. Look at him, he can’t believe it himself…”

“I- it’s okay… Daichi-san.” The genius setter mumbles. “I… didn’t expect this to happen, but I guess… I guess I’m also completely at fault here.”

‘ _Also_ ’?? Both Daichi and Suga muttered to themselves.

“And… who’s the father… of this child…?” Suga reluctantly asked, but he had the vague idea who.

Tobio, with all the overwhelming thoughts of missing out college just as he’s supposed to start, starts to tear up.

“Ts… Tsukishima.”

* * *

**Author's note**

Hello and thank you for reading up until this far. This was supposed to be a oneshot which ended into multi-chapter which I cannot finish as of now due to personal schedule. But of course this rotten mind really needs to step up its game and continue this in the future ugh.

Also, I wanna congratulate myself for my first Haikyuu fic demn wtf to think my first Haikyuu fic isn't KageHina urggggh (lol just kidding, KageTsuki is guilty ship af lol; also reversible couple always my kink urgh


	2. Chapter 2

**Chapter 2**

Seven years later, after technically having run away from his home to Nagoya because of his unexpected pregnancy, Tobio is living the life of a single dad to his adorable son, who he appropriately named _Keito_. [1]

Despite being pregnant right as he was starting university, he managed to finish university. However, it meant that his prospect for volleyball is forever gone, because he had a son to take care instead of dedicating his life to what was supposed to be his main goal in life.

Despite the emotional support Daichi and Suga gave him, part of him almost broke down in those months that he couldn’t play anymore. But when he gave birth to Keito, he was able to move on from the disappointment he had. In fact, he was a doting parent.

Of course, at one point, he was angry at Tsukishima for knocking him up. But considering that it was his fault that he didn’t pull out of Tsukishima back then, this revenge probably just serves him right.

‘ _By the way… how’s that bastard Kei doing right now? I wonder…’_ His mind was wandering. In front of the dinner he cooked, he was blankly staring at the air.

“Papa!” A cheerful young boy exclaimed, excited. Said boy was aged six, has short black hair, and has curly hair that resembled Kei’s.

“Yes, what is it?” He gave a warm smile at his son.

“Today, we had a transferee student from Tokyo. His name is Yuuto, a quiet boy.” Keito enthusiastically said as he scooped a spoonful from the cheesy hamburger his father cooked.

“And then?” Tobio earnestly anticipated for his son’s story.

“My classmates were telling me that we looked similar, though, but I don’t think so… I mean, his hair is blonde, while I have black. My eyes are golden brown, while his is almost black.”

“Hee…” The older Kageyama munched on his food when his young boy continued.

“Ah, but my classmates also told me that we both have curly hair.” Keito finished before filling his mouth with food again.

“Hmmm…” The father hummed, somehow nonchalant.

“I’m even good at introducing my name now!” The boy beamed with pride. “I told him my name is spelled as _Kei_ as in firefly and _To_ as in The Big Dipper. Then he told me his name is spelled as _Yuu_ as in the one in hero then _To_ as in to fly.”

“Wow, to think you’re that knowledgeable in meanings already! As expected of my son…” Tobio was impressed, he smiled at the boy before he realized something at the said transferee’s name.

_It was just swapping the two characters that comprise his very own name, Tobio._

“W- wait a second…” Tobio nervously swallowed at the growing anxiousness over the possibility that he was thinking of.

“What is it, Papa?” The boy was oblivious to the growing panic in his father.

“What’s… his surname?” The father almost couldn’t keep his fluster to himself, he stared intently at his son.

“Umm… I think it was… Tsukishima?”

Tobio almost fainted.

The next day, as he was fixing the morning dishes after his son ate and left, he let his company know that he will be off work that day because he isn’t feeling well.

Truth is, he only planned to fetch his son from the Kindergarten in that afternoon as soon as they were dismissed, hoping that he would probably meet Kei.

Kei, who he hasn’t seen for the past seven years.

The father of his son.

And now, possibly the one who he ended up impregnating and also suffered the disadvantages of unplanned pregnancy.

To think he dismissed the very same possibility that made him end up pregnant, despite being an alpha. To think he, himself, didn’t check on everyone who may have had contact with Tsukishima, asking for his whereabouts or whether or not he ended up pregnant after that night.

But he knew that he, himself, became very secretive when it came to his own life. He was afraid of discrimination from society, being an ‘ _alpha-who-got-knocked-up_ ’. He was wallowing in self-pity because he could no longer play volleyball.

All because of a reckless night.

He heaves a sigh.

Afternoon rolls by, and Tobio arrived in the school almost an hour away from dismissal. He seats himself in the swing at a park slightly far from the gates of the Kindergarten.

For the next several minutes, he is in lookout of the people entering and leaving the school, checking whether that curly hair bastard enters the school.

Suddenly, he feels a tap on his shoulder, making him look back, only to see a familiar bespectacled blonde behind him.

“K- Kei!!” Tobio exclaimed as he stood up to face the taller man, startled.

“Tch. Just when I was supposed to be on lookout here for you.” Kei’s eyes narrowed, almost as if with contempt.

“W- what are you doing here in Nagoya!?” Tobio anxiously asked. He could not believe that after all these years, he’d finally meet again Kei.

“I… got transferred due to workplace re-assignment.” The blonde curtly replied. “And you?”

Tobio was startled for a minute before averting his eyes. “I ran away from my family as soon as I graduated college.”

“Hee… That doesn’t sound so king-like.” Kei switched from eyes of contempt into condescending eyes and smile.

“Shut up.” The raven pouted his mouth, his eyes narrowed at the blonde before staring blankly away.

Silence.

After what seemed like centuries, Tobio hesitantly asked, “so, how’s… _your_ son?”

Tsukishima was surprised. He did not anticipate the question. He averts his eyes and looks at a pair of peeking eyes from over a distance.

“W- well… he’s fine, I guess.” He pauses for a while before asking, “how about _yours_?”

“Hmm… he’s doing well…” His words were cut short, his anxiousness overwhelmed him.

“I hope you didn’t rub on him your kingly attitude.” Kei snidely remarked.

“I didn’t. And I hope you didn’t rub on him your horrible personality.” Tobio gave the glasses-wearer a sharp look.

“I didn’t, okay.” Kei replies.

There was a long pause, before Tobio broke it.

“I hope that at least the children get to acknowledge each other as siblings.” Tobio remarked. “But I assume that your ‘sudden’ change of workplace is still too much for your son.”

“Nonsense,” Kei said, adjusting his glasses. “You want the children to acknowledged each other yet your calling Yuuto as ‘ _my_ ’ son. You should also acknowledge him, King.”

Tobio flinched at that remark, anxiousness gripping on him again. “O- of course, I would. I was just thinking… that because you were calling Keito as ‘ _my_ ’ son, you wouldn’t acknowledge him as your child.”

“You already named him after me,” Tsukishima retorts, “do you think I have any other choice?”

Tobio almost felt a vein pop in his head. “You already named Yuuto so lazily after me, though?? And don’t make it sound like you have no choice but to acknowledge the children, okay?? We are equally responsible for drowning into pleasure that night.”

Kei’s eyebrow raised. “Well, I was pleading that The King should not cum inside me but he insisted on doing so.”

Tobio suddenly grew red at Kei’s vulgar words while they were out in the open. “D- don’t speak such w- words in public!!”

“I didn’t expect the King would be this embarrassed.” Kei once more looks at Tobio with a condescending smile. “But I guess I should follow the King’s orders.”

Tobio is growing tired of this repeated referral of him as a ‘King’. “Why can’t you stop using the word ‘King’, though? Don’t tell me you have a fetish towards being ordered by a King?” He couldn’t think of anything better as a retort.

Tsukishima got flustered, averting his eyes. “I didn’t mean it like that though, idiot.”

“Oh, sure.” Kageyama walked towards Tsukishima, eyes bearing meaning of his seriousness.

“You know what,” he began, “I know there’s a proper timing for everything. How about we stop this pointless banter and fetch the children already? Let’s introduce them to each other later.”

Kei looked at him, as if assessing.

But Tobio continued. “I also… want to know what happened to you all these years.”

Kei almost let out a “geh” sound.

“Fine, fine…” The blonde flippantly replied.

As Tobio walked away, the owner of the spying eyes from the distance walked out of his hiding place and revealed himself — it was no other than Yamaguchi Tadashi.

“Tsukki… is it really okay?”

Tsukishima was silent for a moment, before replying: “I guess so…”

* * *

**Author's note:**

I was thinking that while this was supposed to be a oneshot fanfic, I cannot just let the children suffer through a major life event so suddenly. Like Yuuto was supposed to have just transferred, if you add the instant reunion, it's a bit... too muck of a shock for a young child. Lolwtf my behavioural science upbringing coming out at such inconvenient time, huh. LOL

ConCrit is much appreciated! Maybe some suggestions? I'm really thinking of ending it at chapter 3 though.

Name choice explanation: [1]

  * Kei 蛍 already means firefly. I just added the -to 斗 because I can't think of anything else of a good name.
  * Yuuto 雄飛 is just inverting Tobi-o 飛雄 then changing the reading. LOL.
  * _Yuu_ in hero (eiyuu 英 **雄** ) + _To_ in 'to fly' (tobu **飛** ぶ)




End file.
